Loudspeakers

With its improved crossover, mid/bass motor, metal cabinet top and refined tweeter grille, just how does the Signature compare to its 'plain vanilla' 805 D4 sibling [HFN Feb '22]? In practice the distinctive dished forward response 'shape' [Graph 1, below, with 805 D4 plotted in blue] is even more prominent here with a full 8dB midrange dip that precedes a boosted presence and treble (peaking at 10kHz). Response errors increase from ±4.4dB to ±4.9dB here but the L/R pair matching is tighter at 0.5dB (200Hz-20kHz). Meanwhile, the ultrasonic output of the 25mm Diamond Dome tweeter is lifted by 3dB above 20kHz [pink shaded area, Graph 1] and while the primary resonance at 48kHz is necessarily unchanged, its secondary bending/harmonic mode at 70kHz is far better suppressed than in the 805 D4. Back in the audioband and, again, the U-shaped response means sensitivity falls shy of B&W's rated 88dB – 86.1dB (500Hz-8kHz) is more realistic, and lower still at 83.5dB/1kHz (re. 2.83V/1m).

The enhanced 165mm Continuum bass/mid unit now works over a wider 63-600Hz bandwidth (–6dB re. 140Hz) though nearfield analysis still reveals a spurious broad peak at 1.3kHz, also visible as a mode on the CSD plot [Graph 2], the forward response [Graph 1] and via the port. The latter is still tuned to 42Hz, and retains a broad 26Hz-100Hz output that brings the 805 D4 Sig's corrected LF extension down to a low 41Hz (–6dB re. 200Hz). The largest swings in impedance (4.5-45ohm) and phase (±57o) also occur through the bass, resulting in a modest EPDR of 2.1ohm/120Hz – the 805 D4 Sig's diminished sensitivity is traded for good bass extension and ease-of-drive. PM